Sharp PC-G850VS PIC programmer

Sharp PC-G850VS PIC Programmer

The PC-G850VS is a remarkable pocket computer that was only ever sold in Japan. 

 

 

 

One of the features that make it so interesting is a built-in PIC assembler. This can be used to assemble programs for the PIC16F84 or PIC16F84A.  Just assembling code isn't that much fun though, but fortunately you can attach a programming PCB to the 11 pin connector. The PC-G850VS has built-in PIC programming code to match the assembler. There's a design or two on the internet and I designed a PCB around one of them. I added series resistors to the PIO lines as protection and fiddled with the zener diode values but otherwise the circuit was the one I found.